1. Field of Invention
This apparatus relates to the automatic removal of air from sprinkler and standpipe systems without having to hard pipe discharge liquid to a drain.
2. Description of Related Art
To fight fires in modern office buildings, firefighters use a wide variety of tools but are also regularly aided by systems (fire sprinkler and standpipe systems) within the building itself. Modern buildings almost universally include fire sprinkler systems to contain or extinguish fires in the building without human intervention. Modern buildings that have large foot prints or are three stories or more in height are also provided with standpipe systems for manual intervention by either occupants or firefighters.
Fire sprinkler systems generally follow a fairly standardized principle. A liquid firefighting material (including a true liquid, a colloid, a gel, a foam, and any fluid for fighting fires) is maintained in a series of pipes, generally under pressure, which are generally arranged throughout all areas of the building. Attached to these pipes are various fire sprinklers which, when activated, will spray the liquid in a predetermined pattern into a predetermined area. When a fire situation occurs, various sprinklers near the location of the fire will activate by a heat sensitive element included with each individual sprinkler. When a particular fire sprinkler is activated, the liquid in the pipe is dispensed by the fire sprinkler in a predetermined manner. This action dispenses the liquid on the fire and serves to control or extinguish the fire.
Standpipe systems also follow a fairly standardized principle. A liquid fire fighting material (including a true liquid, a colloid, a gel, a foam, and any fluid for fighting fires) is maintained in a series of pipes, generally under pressure, which are generally located in fire resistive enclosures such as stairs and corridors so as to reach all areas of the building. Standpipe systems have three classifications as defined by the National Fire Protection Association Design Standard 14, Standpipe Systems. Attached to these pipes are various valves and sometimes hoses for manual use by building occupants or fire fighters. When a fire occurs a fire hose valve is manually opened allowing liquid to flow through a hose and nozzle manually delivering liquid to the fire, and thereby controlling or extinguishing the fire.
Maintenance must be performed on these fire sprinkler or standpipe systems on a regular basis, sometimes entailing removal and replacement of sections of pipe or other appliances that are part of the system. Almost necessarily during such maintenance, a portion of the fire sprinkler or standpipe system, or the whole system, must be relieved of pressure, drained, and refilled. The process of draining and refilling allows air to enter the system. When the system is refilled air becomes trapped in the system. Such trapped air is a problem in nearly all such fire sprinkler and standpipe systems. Trapped air may cause inefficient operation of the system due to incomplete filling of the system, less effective pressurization and liquid delivery, and other operating problems. Also, trapped air is certainly a cause of corrosion within the system. Not only is the corrosion a problem in itself, because of the possibility of pieces of the corroded system detaching and traveling internally to clog various portions of the system or appliances thereon, but also the corrosion is a cause for the maintenance procedures that lead to potentially more corrosion through the introduction of more air via the draining and refilling process.
Existing valves for the removal of air from other types of contained-liquid systems generally operate in accord with the following principles. As the liquid flows into a pipe or appliance of such a contained-liquid system, the air in the system is displaced upward and into the air release valve which is attached by a connector to the pipe or other appliance, the connector thereby providing an aperture through which air or liquid can flow from the pipe and into the valve. The valve responds differently to air than to liquid, thus allowing air to be released, but not liquid. Where the valve is a float valve, air flows into a chamber and pushes a float or ball upwards within the chamber. The displaced float then allows the air to push around the float and escape out a hole in the top of the chamber. The float is constrained within the chamber by the connector and hole, as the float is generally too large to pass through either.
As the liquid level rises, liquid eventually flows through the connector and into the chamber. This action then pushes the float upward as the liquid level continues to rise. Eventually, the float is pushed up against the top hole by the underlying liquid which plugs the hole and prevents any further liquid (or air) from traveling through the hole. Generally when the hole is so plugged, most of the air has been removed from the pipe or appliance and the pipe or appliance is in its preferred operational state. The pipe or appliance is now preferably generally sealed to the outside world. Inherently, however, some liquid is discharged as the air is vented through such a air release valve, thus rendering the device unuseable in or over finished spaces. Two air valve systems which operate according to, his principle are shown in U.S. Pat. Nos. 4,708,157, and 4,104,004, the entire disclosures of which are herein incorporated by reference.
Problems with traditional air release valve designs arise from the discharge of some liquid during normal operation, and the possibility of large discharges upon eventual failure. Over the course of time, contained-liquid systems, of which such air release valves are a part, will be drained and refilled with liquid many times. During each of these drain and refill events, the air release valve will unseal, allow air and some liquid to escape, and then reseal. After a sufficient number of such drain and refill events the seal will wear to the point that it no longer completely seals the hole, and will then allow a constant flow of liquid to escape.